Means for a combustion engine having a super charger

ABSTRACT

The invention relates to an arrangement pertaining to internal combustion engines ( 1 ) that include a supercharger ( 6 ) and an intermediate cooler ( 13 ) mounted in a casing ( 4 ). The intermediate cooler includes tubular elements ( 14, 15 ) through which coolant flows for cooling the combustion air compressed by the supercharger ( 6 ). Conventional arrangements of this kind take up a significant amount of space, which is difficult to find in a typically crowded engine space, and also result in undesirable heating of the engine space. A significant improvement has been achieved in these respects by means of the present invention, which is characterized in that the tubular elements ( 14, 15 ) are housed in a cylindrical housing ( 16, 17 ) which includes longitudinally extending slots ( 20, 21 ) and which forms in the casing ( 4 ) a partition wall which is broken by said slots ( 20, 21 ) through which the compressed combustion air is intended to pass into and out from the spaces between the tubular elements ( 14, 15 ) and the housing.

This application is a U.S. National Phase Application under 35 USC 371of International Application PCT/SE99/02292 (published in English) filedDec. 8, 1999.

The present invention relates to an arrangement pertaining to aninternal combustion engine that includes a supercharger for compressionof the combustion air delivered to the engine and a cooler for coolingthe compressed combustion air by means of a heat exchanger through whicha coolant flows, said arrangement being of the kind defined in thepreamble of claim 1.

Compression of the combustion air, normally designated charge air,results in undesirable heating of the air. It is therefore usual toallow the charge air to pass through an intermediate cooler on its wayto the engine. It is difficult to find space in the normally well-filledengine space to accommodate an intermediate cooler and, furthermore, thecooler must be secured in the engine space with the aid of robustfasteners, which also applies to the actual supercharger itself. Alsorequired are hoses and fasteners that interconnect the supercharger andthe inter intermediate cooler. Furthermore, it is necessary thatsufficient room is available to enable connections and said parts to beinspected and serviced.

The object of the present invention is to provide a simple solution thatis well adapted to overcome these problems.

This object is achieved in accordance with the invention with anarrangement that has the characteristic features set forth in claim 1.An extremely compact and effective intermediate cooler that can besecured easily to the engine has been provided by placing the coolingmeans, the intermediate cooler, in a casing which has outlet ports inimmediate connection with the inlet ports of the engine and by designingthe cooling means in the manner disclosed and locating said meansopposite at least the major part of the outlet openings, such that thecooling means will be contacted by the charge air exiting through theoutlet openings along the whole of its length.

In the embodiment defined in claim 2, the casing forming thedistribution chamber is stably constructed with an openable cover thatenables the heat exchanger to be withdrawn from the casing forinspection and cleaning purposes and then easily replaced in the casing.As disclosed in claim 5, in the case of this particular, which includesa housing integrated with the casing and accommodating said heatexchanger, it is possible to use the casing as a supercharger supportmeans when necessary, such supportive use also applying in otherrespects. The casing is sufficiently strong for this purpose and alsoconducts the hot charge air from the supercharger outlet direct to theheat exchanger of the cooling means and from there to the cylinderswithout heating any intermediate hose connections.

One preferred embodiment of the arrangement has the characteristicfeatures set forth in claim 3, whereby uniform cooling of the charge airto the various cylinders is achieved.

The invention will now be described in more detail with reference tovarious embodiments of inventive arrangements and also with reference tothe accompany schematic drawings, in which

FIG. 1 illustrates in perspective an internal combustion engine equippedwith a supercharger and a cooling means, shown partly cut away;

FIG. 2 is a side view of a supercharger and a cooling means casing shownin section;

FIG. 3 is a sectional view taken on the line III—III in FIG. 2;

FIG. 4 is a sectional view taken on the line IV—IV in FIG. 2;

FIG. 5 is a view seen against the casing outlet openings in FIG. 3;

FIG. 6 is a longitudinal section view through one end of the heatexchanger shown in FIG. 1;

FIG. 7 is an end view of the heat exchanger shown in FIG. 6; and

FIG. 8 is a longitudinal sectioned view through the heat exchanger ofFIGS. 6 and 7 with surrounding housing, and shows cover members whichclose the ends of said housing.

FIG. 1 illustrates the contours of a four-cylinder in-line internalcombustion engine 1 having four inlet ports 2 connected to openings 3 ina casing 4 which forms a distribution chamber 5 for the compressedcombustion air exiting from a supercharger 6. The superchargercommunicates with the distribution chamber 5 through an opening 7 in themutually opposing walls of the casing 4 and the supercharger 6. In theillustrated case, the supercharger 6 includes a helical rotor compressorwhich includes two rotors, of which one is adapted to be driven by apulley 8 which is connected to the engine crank shaft and which drives apulley 10 connected to said rotor via a toothed belt 9. The superchargerhas connected to an air purifier (not shown) an inlet port 12 thatincludes a regulating valve means 11. Although not shown, thesupercharger 6 is firmly screwed to one side of the engine and thecasing 4 is screwed firmly to the upper side of the supercharger andalso connected with the four inlet ports or induction ports 2.

The casing 4 houses a cooling means 13 which includes two mutuallyparallel and series-connected heat exchanger tubes 14, 15 which extendin front of the openings 3 to the inlet ports 2 as seen in the flowdirection of the combustion air, and include external fine, transversallamellae between the compressed combustion air flows whilst guided byhousing 16, 17 surrounding said tubes and provided with axiallyextending slots 20, 21. Coolant flows axially through the tube 15 in onedirection and through the tube 16 in the opposite direction via inletand outlet stubs 18, 19 connected by hoses (not shown) to a separatecooler K which is cooled by the slipstream generated.

FIGS. 2-8 illustrate generally the same supercharger and cooling means,intermediate cooler, as those described above although the embodimentillustrated is adapted for the supply of cooled charge air to aninternal combustion engine that has five cylinders. As will be seen fromFIG. 2, the casing 4 and the supercharger 6 attached thereto are mountedas a single unit on the engine (not shown), by virtue of having pushedthe openings 3 in the casing 4 over the inlet ports 2 of the engine, andthereafter tightening the supercharger 6 against the engine with the aidof fastener flanges 22 and screw fasteners 23, with the toothed belt 9mounted on respective pulleys 8 and 10.

As will be evident from FIG. 2, the charge air exiting from thesupercharger 6 is pressed through the opening 7 into the induction ports2 of the engine, via the distribution chamber 5. The charge air musttherewith pass the cooling means 13 shown in FIG. 1 and represented inFIGS. 2 and 3 by the housing 16, 17 provided with said axial slots 20,21, in which the heat exchanger tubes 14, 15 (shown in detail in FIGS.6, 7 and 8) provided with said external cooling fins can be inserted.The housing 16, 17 can be closed on one side by means of two covermembers 24, 25 provided with pipe stubs 18, 19, and on the other side bymeans of a cover member 26 which forms an overflow passageway for liquidcoolant introduced through the pipe stub 18, and further through fine,axially extending passageways 27 in the wall of the tube 14 and thenback through fine, axially extending passageways 28 in the wall of thetube 15 and from there out through the pipe stub 19. As beforementioned, the tubes 14, 15 are provided externally with fine peripheralcooling fins 29. As will be seen from FIG. 8, an O-ring is fitted ateach end of the tubes 14, 15, between the outermost cooling fins 29 andrespective cover members 24, 25, 26 so that the coolant will be led tothe passageways 27, 28 and prevented from coming into contact with thecooling fins 29.

The actual cooling means 13 is comprised of the heat exchanger tubes 14,15 illustrated in FIGS. 1 and 6-8, wherewith the charge air flowsbetween the lamellae 29 of said tubes in the cross-direction thereof,said tubes being cooled by the liquid coolant that flows in a closedcircuit formed by the passageways 27, 28 and the cooler K and the hoseconnections (not shown) connected between the cooler and the pipe studs18, 19. The charge air is guided in intimate contact with the lamellae29 through the tube housings 16, 17 which through the medium of slots20, 21 direct the flow of charge air directly to the major part of theoutlet openings 3 and indirectly to the two outermost openings 3, asillustrated in FIGS. 3-5 when found necessary for space reasons. Airwill nevertheless be distributed uniformly to all outlet openings 3. Byusing two series-connected heat exchanger tubes 14, 15, the temperaturedistribution of the cooled charge air is also uniform in respect of alloutlet openings 3.

It will be understood that the inventive arrangement can also be used incombination with V-type internal combustion engines, in which case thesupercharger with intermediate cooler can be placed between the rows ofcylinders with the outlet openings 3 facing in opposite directions.

It will also be understood that the invention is not restricted to theillustrated and described embodiments thereof and that modifications canbe made within the scope of the invention defined in the accompanyingClaims. For instance, other types of elongate heat exchangers may beused. Furthermore, other types of superchargers are conceivable, forinstance superchargers that are driven by engine exhaust gases, eventhough such solutions are less beneficial than the solutions illustratedin this document.

It is assumed that the coolant used is water, optionally with a glycoladdition. In certain running conditions, e.g. in the case of highambient temperatures, the intermediate cooling facility may beinsufficient. It has been found that an increase in the temperature ofthe inlet air by only some degrees will have serious, unexpecteddrawbacks with respect to engine operation. Amplified cooling can bevery significant in this respect, and consequently it may be expedientto use to this end a coolant used typically in a cooling plant,preferably a coolant used in an air-conditioning plant.

What is claimed is:
 1. An arrangement pertaining to an internalcombustion engine (1) that includes a supercharger (6) for compressionof combustion air delivered to said engine, and a cooling means (13) forcooling the compressed combustion air by means of a heat exchanger thatincludes tubular elements (14, 15) through which a coolant flows andwhich are contacted externally by the compressed combustion air, whereinengine cylinder induction ports (2) are connected directly to outletopenings (3) allocated to respective induction ports, wherein saidoutlet openings (3) are formed in a casing (4) which communicates withthe supercharger (6) and which forms a distribution chamber (5) for thecompressed combustion air and in which the tubular elements ( 14, 15) insaid heat exchanger are mounted in front of at least the major part ofthe outlet openings (3), wherewith the compressed combustion air flowstransversely to the outlet openings (3), characterised in that thetubular elements (14, 15) of the heat exchanger are housed in acylindrical housing (16, 17) that includes longitudinally extendingslots (20, 21) and that forms integral with said casing a partition wallwhich is broken solely by the slots (20, 21 ) through which thecompressed combustion air is intended to pass into the spaces betweenthe tubular elements (14, 15) and the housing and out through saidspaces in a direction towards the outlet openings (3) in said casing. 2.An arrangement according to claim 1, characterised in that the casing(4) is provided at least at one end of the cooling means (13) with anopening that extends through the wall of said casing (4), said openingbeing intended to permit said tubular elements (14, 15) to be insertedinto the housing (16, 17), and wherein said opening can be closed with acover member (24-26) that includes a coolant inlet (18) and a coolantoutlet (19).
 3. An arrangement according to claim 1, wherein the heatexchanger includes two mutually parallel and series-connected tubes (14,15) through which liquid coolant flows.
 4. An arrangement according toclaim 1, wherein the tubular elements (14, 15) of said heat exchangerinclude external, transversal lamellae (29) that extend radiallyoutwards to the surrounding housing (16, 17).
 5. An arrangementaccording to claim 1, wherein the casing (4) forming said distributionchamber (5) has a wall that includes an inlet opening (7) for compressedcombustion air, wherein the supercharger housing is positioned againstsaid wall with a compressed combustion air outlet opening (7) thatcoincides with the casing inlet opening (7).
 6. An arrangement accordingto claim 2, wherein the heat exchanger includes two mutually paralleland series-connected tubes (14, 15) through which liquid coolant flows.7. An arrangement according to claim 6, wherein the tubular elements(14, 15) of said heat exchanger include external, transversal lamellae(29) that extend radially outwards to the surrounding housing (16, 17).8. An arrangement according to claim 2, wherein the tubular elements(14, 15) of said heat exchanger include external, transversal lamellae(29) that extend radially outwards to the surrounding housing (16, 17).9. An arrangement according to claim 3, wherein the tubular elements(14, 15) of said heat exchanger include external, transversal lamellae(29) that extend radially outwards to the surrounding housing (16, 17).10. An arrangement according to claim 2, wherein the casing (4) formingsaid distribution chamber (5) has a wall that includes an inlet opening(7) for compressed combustion air, wherein the supercharger housing ispositioned against said wall with a compressed combustion air outletopening (7) that coincides with the casing inlet opening (7).
 11. Anarrangement according to claim 3, wherein the casing (4) forming saiddistribution chamber (5) has a wall that includes an inlet opening (7)for compressed combustion air, wherein the supercharger housing ispositioned against said wall with a compressed combustion air outletopening (7) that coincides with the casing inlet opening (7).
 12. Anarrangement according to claim 6, wherein the casing (4) forming saiddistribution chamber (5) has a wall that includes an inlet opening (7)for compressed combustion air, wherein the supercharger housing ispositioned against said wall with a compressed combustion air outletopening (7) that coincides with the casing inlet opening (7).
 13. Anarrangement according to claim 4, wherein the casing (4) forming saiddistribution chamber (5) has a wall that includes an inlet opening (7)for compressed combustion air, wherein the supercharger housing ispositioned against said wall with a compressed combustion air outletopening (7) that coincides with the casing inlet opening (7).
 14. Anarrangement according to claim 7, wherein the casing (4) forming saiddistribution chamber (5) has a wall that includes an inlet opening (7)for compressed combustion air, wherein the supercharger housing ispositioned against said wall with a compressed combustion air outletopening (7) that coincides with the casing inlet opening (7).
 15. Anarrangement according to claim 8, wherein the casing (4) forming saiddistribution chamber (5) has a wall that includes an inlet opening (7)for compressed combustion air, wherein the supercharger housing ispositioned against said wall with a compressed combustion air outletopening (7) that coincides with the casing inlet opening (7).
 16. Anarrangement according to claim 9, wherein the casing (4) forming saiddistribution chamber (5) has a wall that includes an inlet opening (7)for compressed combustion air, wherein the supercharger housing ispositioned against said wall with a compressed combustion air outletopening (7) that coincides with the casing inlet opening (7).